Flue-mounted humidifier



FIG. 1 is a front view with the back view being identical in appearance;

FIG. 2 is a bottom view;

FIG. 3 is a front view, (back view is identical);

FIG. 4 is a side view with the opposite side view being identical in appearance. 

Then ornamental design for a flue-mounted humidifier, as shown and described. 